C900 HEAD GASKET Replacement
Introduction
Introduction
This DIY section was created because of a shortage of money and a need to get my SPG back on the road.
After paying $1000 for my mechanic to put the head on the car 2 months ago, I wasn't ready to do it again.
Since, I had just replaced the intake manifold with the yellow one, I knew at least 50% of the job was doable.
Last year I replaced the cams on the car, so that was another 10% I knew how to do. Last year I also replaced the turbo, so that was another 10% of experience.
Basically, the only part I had never done before was removing the head. I figured there was no better time than the present.
First things first. Get a couple of boxes that are about the size of a case of beer.
If you're like me you'll have a couple of empty beer boxes ready to be put to work!
You will also need the Bentley repair book and 1 special tool.
The Bentley book should be right next to you so you can refer to it for anything I may have missed or wasn't clear about.
The special tool you need is an E-16 torx socket.
I got the set of torx sockets from Sears for about $20. I don't think they are the highest quality and they are only 3/8" drive, but they work.
I would strongly recommend you find a 1/2" drive E-16 Torx socket before beginning this task.
Eeuroparts sells a nice headgasket kit that contains almost everything you need. I do not think it includes the turbo oil gaskets or the turbo oil return o-ring.
These are good to replace as they tend to leak after being messed with.
NOTE: For those that have a 2.1 head and intake manifold on the car, you will need a 2.1 intake manifold gasket. You will still use a 2.0 head gasket.
There are a bunch of other things you can do as preventative maitenance. This includes, belts, waterpump, alternator bushings, timing chain tensioner, etc...
Another area to lookout for is rusted and broken exhaust and turbo studs. These get very brittle with age.
Snap-on carries some very handy tools for removing broken studs.
The first is cobolt reverse thread drill bits. These allow you to drill out the stud in reverse which sometimes pulls out the stud along the way.
They also carry a super fancy stud removal tool. It basically latches on to the stud and you unscrew the stud using the tool.
These tools are not cheap, but they work very well. I have both in my toolbox.
No matter what, I highly recommend you pull out all of the studs in the head and replace them with new ones. I bought some very expensive ones from www.summitracing.
Basically, you need a M8 x 1.25 thread by 45mm (1.75") long. The ARP part # is ARP-400-8013 and retails for about $72.
Let's Begin!
C900 HEAD GASKET Replacement
Introduction
Introduction
This DIY section was created because of a shortage of money and a need to get my SPG back on the road.
After paying $1000 for my mechanic to put the head on the car 2 months ago, I wasn't ready to do it again.
Since, I had just replaced the intake manifold with the yellow one, I knew at least 50% of the job was doable.
Last year I replaced the cams on the car, so that was another 10% I knew how to do. Last year I also replaced the turbo, so that was another 10% of experience.
Basically, the only part I had never done before was removing the head. I figured there was no better time than the present.
First things first. Get a couple of boxes that are about the size of a case of beer.
If you're like me you'll have a couple of empty beer boxes ready to be put to work!
You will also need the Bentley repair book and 1 special tool.
The Bentley book should be right next to you so you can refer to it for anything I may have missed or wasn't clear about.
The special tool you need is an E-16 torx socket.
I got the set of torx sockets from Sears for about $20. I don't think they are the highest quality and they are only 3/8" drive, but they work.
I would strongly recommend you find a 1/2" drive E-16 Torx socket before beginning this task.
Eeuroparts sells a nice headgasket kit that contains almost everything you need. I do not think it includes the turbo oil gaskets or the turbo oil return o-ring.
These are good to replace as they tend to leak after being messed with.
NOTE: For those that have a 2.1 head and intake manifold on the car, you will need a 2.1 intake manifold gasket. You will still use a 2.0 head gasket.
There are a bunch of other things you can do as preventative maitenance. This includes, belts, waterpump, alternator bushings, timing chain tensioner, etc...
Another area to lookout for is rusted and broken exhaust and turbo studs. These get very brittle with age.
Snap-on carries some very handy tools for removing broken studs.
The first is cobolt reverse thread drill bits. These allow you to drill out the stud in reverse which sometimes pulls out the stud along the way.
They also carry a super fancy stud removal tool. It basically latches on to the stud and you unscrew the stud using the tool.
These tools are not cheap, but they work very well. I have both in my toolbox.
No matter what, I highly recommend you pull out all of the studs in the head and replace them with new ones. I bought some very expensive ones from www.summitracing.
Basically, you need a M8 x 1.25 thread by 45mm (1.75") long. The ARP part # is ARP-400-8013 and retails for about $72.
Let's Begin!
C900 HEAD GASKET Replacement
Disassembly
Disassembly
I first started with the easy stuff. It's so easy that I didn't even take any pictures of it.
At this point your car should look like this:
C900 HEAD GASKET Replacement
Disassembly
Disassembly
Now it's time for the fun stuff!
Undue the throttle cable from the throttle body. To do this you simply use a straight screwdriver and pry apart the metal.
Then undue the 2-10mm bolts and the throttle cable is free.
There are 2 wires that are connected to the throttle body. Disconnect these!
Now you can undue that 15mm bolt that is holding the throttle body to the engine.
Since, I have a custom fuel line. I have to remove the fuel rail first, then I can get room to remove the A/C Compressor.
The fuel rail is held on by the 2 17mm fuel lines bolts and the 2 13mm bolts.
Once all of the bolts are out, you unplug all of the injectors, and then pull up on the rail. The injectors are attached to the fuel rail and they will come out of the intake manifold too!
I then removed the fuel pressure regulator.
Now it's time to get the A/C Compressor out of the way!
Take off the belt and A/C Idler pullet
You can either remove the compressor and bracket separately or you can remove the bracket with the compressor still attached.
I prefer the latter way because it's faster (3 bolts rather than 4!).
Place the A/C Compressor on your windshield underneath a towel and get it out of the way!
This is what your car should look like!
C900 HEAD GASKET Replacement
Disassembly
Disassembly
We're almost ready to pull the intake manifold.
Move all of the fuel injection wiring out of the way. There are a couple of ground wires that need to be unhooked.
Unscrew the coolant bolt that connects to the turbo.
Finally, remove the coolant hose that goes to the heater core.
Now undue the 12mm bolts that hold the intake manifold onto the head and pull it off of the car!
All of that nice color is gone! Now it looks like an engine that has 192,000 miles on it.
The next thing to remove is the turbo charger if you have one.
Be sure to pick up a turbo-seal kit from the dealer so you can replace the seals when re-installing the head!
The turbo is rather easy to remove. Undue the oil lines and water lines.
Unbolt the downpipe from the turbo and finally unbolt the turbo from the exhaust manifold.
Twist and turn the turbo out of the car.
C900 Head Gasket Replacement
Disassembly
Disassembly
It's time to get serious about removing the head!
I didn't remove the exhaust manifold, as it really isn't necessary to regular head gasket replacement.
Also, since the studs do not come off very easily, it is much easier to replace them on the bench than on the block.
Some people also keep the intake manifold on the head. I'm not sure how they can lift the head with both intake and exhaust attached, but it can't be easy.
Even with just the exhaust and cams attached, the head must weigh one hundred pounds.
Let's get this started by removing the valve cover.
Be very carful with your bolts and tools at this point. You don't want to drop anything down the timing chain hole!
Now you need to set the engine to Top Dead Center.
Removing the spark plugs will eliminate compression and make this easier!
You can use the starter to move the engine a little bit at a time. Once you get close, use a screwdriver to move the flywheel to the exact position.
The cams marks should be very close to the pointers. If they are way off, then you need to rotate the engine another 180 degrees.
Remove the timing chain tensioner. It's the big nut underneath the A/C Bracket.
If you remove the little bolt first, you will be able to measure the play in the timing chain by looking at how extended the tensioner has moved.
I believe the max amount is 11mm or something.
Using a wrench on the cam and a wrench on the sprocket, remove the bolts on the chain sprockets. Be very careful not to drop the bolts down the engine!
Wrap a coat hanger around the timing chain so that you can fish the chain out of the engine if it falls in!
Now take your E-16 torx socket and loosen the head bolts 1/4 turn in the same sequence as tightening them. This sequence can be found in the Bentley manual.
The bolts should still be somewhat tight at this point. Now go back through the same sequence and remove all of the bolts.
In the Bentley book it says to place a dowel or special tool back into the head. This is so you can lift the head straight up.
This is not required, but it does really make it easier to pull and drop the head on the engine.
The head will be stuck on the engine pretty good. You need to pry it off and then lift it up. This is much easier with a helper.
One person pulls the head while the other prys it. Lifting it off of the engine is also easier with a helper.
There are 2 pins that the head sits on. You must lift the head straight up and clear both of these pins.
The timing chain can simply be moved through the head and rest on the engine while lifting the head.
Since you have the coat hanger wrapped around the chain, the chance of losing the chain in the engine is very low.
If you didn't unscrew the big coolant drain bolt in the block, the pistons will look like this picture.
Clean out the cylinders with some paper towels.
If you're going to leave the head off of the engine for a day or more, rub the 2-3 cylinder walls with motor oil to keep them from rusting.
At this point you are ready for another beer while you analyze your engine and head.
Look at the gasket and try to find the failure. If the gasket was leaking coolant into a cylinder, you should have one very shiny piston.
Clean the dome with brake cleaner and look for small cracks between the valves. This is the most common place for cracks.
Check your pistons for cracks or dents. If you had a valve hit the piston, the piston may need to be replaced!
Now it's time for installing the new gasket and re-assembly.
C900 Head Gasket Replacement
Reassembly
Reassembly
In order to ensure a good seal with the new gasket, you need to clean up the block and head to a nice smooth surface.
Using a wire brush, you can remove the excess gasket material. Finish it off with some brake cleaner or laquer thinner.
At this point it's a good idea to use a thread chaser and run it down the head bolt holes to make sure the threads are clean.
This will make sure your torque readings are accurate.
Since the exhaust manifold and cams were attached to the head, it was rather heavy. I had a friend help me lift the head onto the block and onto the samll studs.
I tried to use the wood dowels as Bentley suggested, but I found that they got into the way and I ended up throwing them across the garage!
With two people, you can drop the head down straight and not worry about the dowels.
Now it's time to tighten it down. I choose to use the old bolts.
Bentley recommends that you use new head bolts because the bolts stretch and then lose their ability to hold the torque.
I measured mine and the length was within 1 mm of each other, so I reused them.
Use the Bently book for the tightening sequence.
Basically, you start from the center and work your way to the ends in a circle pattern.
You may want to put some lube on the bolts to make sure they do not bind in the holes, however you want to be careful that the oil is not to slick.
It can throw off your torque readings! Bentley doesn't say anything about oiling the bolts, so it's up to you!
Turning the bolts the additional 90 degrees was surprising difficult! I was afraid that I would break either the 3/8" E-16 socket or the 3/8"->1/2" converter.
After this first job, I have since bought a 1/2" E-16 socket to make sure I can really torque down the bolts without any worries.
C900 Head Gasket Replacement
Reassembly
Reassembly
Now it's time to re-install the timing chain and cam sprockets.
This is the make or break part of the job. If you mess up this part, you could seriously damage your engine!
I spent a good hour on this making sure it was right.
The Bentley goes into great detail on this, so be sure to check out that section!
You first need to make sure the engine is at TDC (Top Dead Center) on cylinder #1.
This should already be done before removal, so this should just be a double check.
Cylinder #1 is the one closest to the firewall!
You can feel for TDC by feeling the air through the spark plug hole.
Once it's at the top, check the flywheel to make sure the flywheel mark is lined up with the timing line.
If it's not you will have to turn the engine another 180 degrees.
Install the intake cam (upper cam) sprocket first. (I'm assuming the cams are already installed on the head...)
Get the chain as tight as possible from the tensioner end and slip the sprocket onto the chain.
Once you get that sprocket on, the chain should just slide over the exhaust sprocket as the intake sprocket is holding the chain in place.
Hand tighten both cam sprocket bolts and insert the timing chain tensioner.
It's time to make sure the cam marks are lined up with the engine.
I used a big screwdriver to turn the engine counter-clockwise a little bit at a time.
DO NOT TURN THE ENGINE BY THE CAMS!!!
The cam is not designed to turn the whole engine!
I made sure the engine went through 2-4 full cycles and then rechecked the flywheel timing mark and the cam marks.
My cams were off about 0.5 mm, but both cams were the same so I figured it was okay.
Now you can tighten down the cam sprocket bolts to 47 ft/lbs.
The hard part is done! It's time for a beer break.
C900 Head Gasket Replacement
Reassembly
Reassembly
From here on out it's just a matter of bolting everything back up.
TIPS:
I found that if you attach the tube to the turbo first it really makes life much easier. Do not tighten the bolts that connect the turbo to the exhaust manifold. This allow you wiggle room to get the O-ring into the block. Then you can use move the turbo to force the tube into the hole. You can also put some soapy water on the O-ring to help it go in.
When you start the car up for the first time look just let it sit and idle for a good 10-15 minutes and look for the following:
There could be some coolant in the exhaust, but you really should not see smoke much past a couple of minutes. If you do, then you need to start looking at things.
In most cases this is why the head gasket blew in the first place. Be sure you have fixed the actual problem!
Additionally, I have found that both the intake manifold bolts and newly installed exhaust studs seem to loosen up after the first real heat cycle.
Be sure to double check all of those bolts after the first warm-up.
Although everyone says a headgasket doesn't need any break in time, I always allow the engine about 200 miles of regular driving to make sure things were sealed correctly before really opening up the boost.
It's been about 2 years now it is still holding up under 20+ psi of boost!
